was added accidentally, and although not terrible, it would improperly
hide the bug of calling M_PREPEND with a NULL mbuf argument.
Submitted by: jlemon (ISTR)
wrong for many years that negative niceness would lower the priority
of a process below PUSER, and once below PUSER, there were conditionals
in the code that are required to test for whether a process was in
the kernel which would break.
The breakage could (and did) cause lock-ups, basically nothing else
but the least nice program being able to run in some conditions. The
algorithm which adjusts the priority now subtracts PRIO_MIN to do
things properly, and the ESTCPULIM() algorithm was updated to use
PRIO_TOTAL (PRIO_MAX - PRIO_MIN) to calculate the estcpu.
NICE_WEIGHT is now 1 to accomodate the full range of priorities better
(a -20 process with full CPU time has the priority of a +0 process with
no CPU time). There are now 20 queues (exactly; 80 priorities) for
use in user processes' scheduling, and PUSER has been lowered to 48
to accomplish this.
This means, to the user, that things will be scheduled more correctly
(noticeable), there is no lock-up anymore WRT a niced -20 process
never releasing the CPU time for other processes. In this fair system,
tsleep()ed < PUSER processes now will get the proper higher priority
than priority >= PUSER user processes.
The detective work of this was done by me, along with part of the
solution. Luoqi Chen has provided most of the solution, and really
helped me understand what was happening better, to boot :)
Submitted by: luoqi
Concept reviewed by: bde
not u_long. On i386's with 64-bit longs, returning u_longs indirectly
in (more than) the space reserved for uintptr_t's tended to corrupt the
previous frame pointer in the stack frame, so it was not easy to debug.
The type mismatches are hidden by the bogus cast in DEVMETHOD().
declarations of structs for use in prototypes are only necessary if
the struct is not otherwise declared in scope.
Removed prototypes for fdissequential() and fdsequential(). These
functions never existed in FreeBSD.
Fixed most style bugs in FreeBSD changes (mainly disordered prototypes
and prototypes without parameter names).
Correct derivation of Eighth Edition Research UNIX. According to dmr,
it was derived from 4.1cBSD; according to the 4.4BSD book, it was
derived from 4.1BSD. Since dmr did the work, he's more likely to be
correct.
Correct typos.
Remove dead URLs.
Note that if_aue doesn't strictly depend on usb because it uses the
method interface for calls rather than using internal symbols, and
because it's a child driver of usb and therefore will not try and do
anything unless the parent usb code is loaded at some point. if_aue does
strictly depend on miibus as it will fail to link if it is missing.
bus/driver/kobj system. I am not 100% sure that this is the correct fix,
but it is harmless and does seem to solve the problem. At worst, it could
cause a tiny memory leak at unload time - this is better than a free(NULL)
and subsequent panic. I'm waiting for comments from Doug about this.
This may yet be backed out and fixed differently.
The change itself is to increment the reference count on drivers in one
case where it appears to have been missed. When everything is unloaded,
kobj_class_free() was being called twice in some cases, and panicing the
second time.
version dependency system. This isn't quite finished, but it is at a
useful stage to do a functional checkpoint.
Highlights:
- version and dependency metadata is gathered via linker sets, so things
are handled the same for static kernels and code built to live in a kld.
- The dependencies are at module level (versus at file level).
- Dependencies determine kld symbol search order - this means that you
cannot link against symbols in another file unless you depend on it. This
is so that you cannot accidently unload the target out from underneath
the ones referencing it.
- It is flexible enough that we can put tags in #include files and macros
so that we can get decent hooks for enforcing recompiles on incompatable
ABI changes. eg: if we change struct proc, we could force a recompile
for all kld's that reference the proc struct.
- Tangled dependency references at boot time are sorted. Files are
relocated once all their dependencies are already relocated.
Caveats:
- Loader support is incomplete, but has been worked on seperately.
- Actual enforcement of the version number tags is not active yet - just
the module dependencies are live. The actual structure of versioning
hasn't been agreed on yet. (eg: major.minor, or whatever)
- There is some backwards compatability for old modules without metadata
but I'm not sure how good it is.
This is based on work originally done by Boris Popov (bp@freebsd.org),
but I'm not sure he'd recognize much of it now. Don't blame him. :-)
Also, ideas have been borrowed from Mike Smith.
